Mavic Disappeared. Fly Away Unit!!! Input needed

[Death from Above]

Unfortunately I lost my Mavic within less than 5 hours of owning it. Im currently still under going discussion with DJI in regards of replacing the drone. The incident happened during a live FB stream and luckily I have video proof and all flight data which I will provide as well. Any insight into these case would be greatly appreciated.

Flight Data
HealthyDrones.com - Innovative flight data analysis that matters

The Story
The flight started out with no problems and ran just as well as it's madden flight. Being Mavics second flight I decided to try out its new feature Facebook live stream. Flight was normal and I decided to test out its speed and go to a destination and back. When I got to 1600 meters the Mavic suddenly ended the live stream and video screen went black. Controller attempted to reconnect over and over. I waited for it to return home due to the lost of signal but it continued to be disconnected. I then went to the last know position to see if I could find the drone. During the commute over to its location I continued to attempt to reconnect, still nothing. I checked the field and surrounding area with no sign of the drone. Went back to home base and the Mavic was still not seen. Flight data shows that it had plenty of signal in the area the drone stayed within 13-15 satellites at all times with 4-5 bars of connection. Luckily i was at the time video streaming and therefore I have complete footage of the flight drone saved. At the time the Mavic lost signal it had 13 satellites, normal flight mode, and 67% battery left. I have no idea what happened and Mavic continues to be missing.

At this point all DJI techs have concluded is that the flight was normal and had no abnormalities but they believe it crashed into the larger building it passed by. Below is my response to that statement.

My Response
To whom it may concern,
I’m lost and baffled how your results are inconclusive and yet I'm still been held liable for the loss of your product. Agreeing with what was stated yet offering a discount for the loss of drone doesn't justify the safe fails your product carries to prevent such incidents.
1 & 2) As your technician stated the flight record ended suddenly without any justification of loss of signal “without any sign of abnormality”. Please clarify how thats not an issue with a defect or a malfunction that causes a loss of sudden signal, clearly something went wrong.
3)Let me remind you what's stated on your site in more information about the Mavic. Attached below is a copy of the statement in Bumps and Scrapes section.
As the Mavic flies, dual forward and downward vision sensors measure the distance between itself and obstacles by taking photos from all four cameras and using the information to create a 3D map that tells it exactly where obstacles are. The dual forward and downward vision sensors require visible light to function, and in bright light can see as far as 49ft (15m) out in front.This obstacle avoidance system is activated in every Intelligent Flight Mode including all ActiveTrack modes, TapFly and Terrain Follow. It is also available during automatic Return to Home, so that the Mavic can easily make its way back without bumping into anything in its path.

Stating that the drone possibly crashed into a building on its return home flight therefore can’t be justified based on its obstacle avoidance features.
Assuming that it hit the building therefore can’t be justified for its capable features. Even if the drone came across the obstacle it could have gone around the building with still plenty of battery life left.
The live stream video further illustrates further how nothing came across the drone to cause it to crash nor did it act in any other abnormal mid flight up to the point it suddenly lost connection.
Please have a technical or a representative call me before the end of the day to further discuss this matter.

DJI once again claims without any further data everything is normal and anything could have happened to the drone. So I guess losing perfect signal is completely normal and not returning home as it should is completely okay. I have constantly gone back to search for the drone, but still no luck of finding it.

Any advice would be greatly appreciated. Thank you

 

[msinger]

Please upload your TXT flight log here and post a link back here.

 

[Death from Above]

Please upload your TXT flight log here and post a link back here.

Phantom Log Viewer - PhantomHelp.com

Done

 

[JohnC]

Not an expert, direct path back from end of the flight log would bring it very close to the 'S' shaped building just below the small lake, your RTH was set to 98 feet, unless smart RTH was enabled then it would, assuming the building is higher than the 98 feet, would stop, hover, battery goes flat then lands. Its where I would be looking while msinger works his magic.

 

[msinger]

You lost the remote controller signal because there was a tall building between you and the Mavic. When it attempted to return home, it crashed into the building below since you had the RTH altitude set to 30 meters:



Look for your Mavic on the roof here:

 

[AAPhoto]

Was the drone within visual line of sight? This is one of the FAA rules and could have prevented all of this. Let's hope the drone didn't injure anyone or cause property damage.

As for the obstacle avoidance you mentioned in your response to DJI, there are limitations. First, did you have obstacle avoidance enabled? Horizontal avoidance? Reverse flying enabled? If everything was enabled, it could have flown horizontally or backwards into another obstacle. Even with only the front obstacle avoidance enabled, there is a limit as to how high or how far around the drone will attempt to go. Earlier this week, that was the case with another member. His drone attempted to go over a tall building, climbed to try to go over it, reached its limit (I can't recall how far it actually will climb), started going forward again, and crashed right onto the window of a skyscraper.

As for the signal loss, it's most likely due to the drone ending up behind a building, trees, or other tall structures that could have caused interference or blocked the signal.

As with every case posted here, I'm sure the experts in this forum will provide detailed information as to exactly what happened and most likely even help you find your Mavic. I wouldn't expect DJI to replace your drone in this case, unless you purchased the DJI Care Refresh option. Good luck!



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[JohnC]

What he said!

I don't really understand why anyone would send a flying machine away having owned it for less than 5 hours = no experience so the poor thing was doomed, if not today then soon.

I hope you get it back and I hope you take stock of the situation and find an open space to learn to fly the aircraft first, knowing its and your limitations is paramount to safe flight in or with any aircraft.

Its not DJI's fault, the technology did what you asked it to do, there is no excuse for poor airmanship. If I fly my Phantom or Mavic out of sight (over woodland or farmland never over buildings) then I accept that I do so at my risk. I accept that the electronic flight aids are just that and that I am ultimately the pilot.

Just chalk it up to pilot error and I hope you find it and there's no harm done. We are all capable of making errors of judgment, the learning is from accepting it.

 

[4wd]

They only state the obvious, there is no fault displayed.
You were quite low to be way beyond line of sight with buildings taller than your height.
The Obstacle Avoidance isn't foolproof and can't see thin wires and such.

If they offer a discounted replacement that seems quite generous.

 

[Death from Above]

Thanks guys for the input. Yeah the obstacle avoidance feature definitely isn't fool proof as I can see. Im going to go check out that building on my lunch break and see if I can find it on the roof. I will keep you guys updated. If I can't find it I will most likely take the discount since I need the drone for work.

 

[msinger]

the obstacle avoidance feature definitely isn't fool proof as I can see

FYI -- by default, the following setting is disabled in DJI GO:

 

[Death from Above]

I did enable all the features but who knows at this point.


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[msinger]

Even if the sensors were all enabled (the log does not contain that info), they aren't perfect. Always set the RTH altitude to the proper altitude before taking off.

 

[raberrio]

The "enable obstacle avoidance" option, which "if activated, aircraft will avoid obstacles horizontally", may cause a crash? Which is the aircraft expected behaviour with this option enabled, when it reaches an obstacle?

thanks!

 

[AAPhoto]

The "enable obstacle avoidance" option, which "if activated, aircraft will avoid obstacles horizontally", may cause a crash? Which is the aircraft expected behaviour with this option enabled, when it reaches an obstacle?

thanks!

For new pilots, it may be best to have only the front obstacle avoidance enabled and none of the additional features. This will enable the drone to simply hover in place to give you time to decide what needs to be done. Otherwise, if the drone fly's horizontally or backwards to avoid an obstacle, it could hit another obstacle to the side, or behind it (remember, it can't see those).

 

[raberrio]

For new pilots, it may be best to have only the front obstacle avoidance enabled and none of the additional features. This will enable the drone to simply hover in place to give you time to decide what needs to be done. Otherwise, if the drone fly's horizontally or backwards to avoid an obstacle, it could hit another obstacle to the side, or behind it (remember, it can't see those).

thanks, then i will disable that option for a while

 

[MavicKhan]

One of the initial steps of the pre-flight checklist should be to evaluate the direct line-of-sight highest obstacle, then estimate any even higher obstacles that might be beyond visual range you might intend to fly to (...if your country legislation has provisions for flying BVLOS under certain conditions...) and then set the RTH height accordingly in the app (...with obstacle avoidance turned off until DJI straightens out the into-the-low-sun problem).

To help me with this I've now made a point of starting each session with a vertical ascent to my estimated clearance height, gimbal leveled, and perform a 360º in-position complete turn to make it visually clear to me that obstacles are well cleared at that height.

I then fly with confidence knowing that, should any RTH mode be engaged, the Mavic, if not malfunctioning, will do its thing as it was built and programmed to do.

Just yesterday I made my first BVLOS test and, because my level was below the Mavic and some obstacles were on the way, I eventually lost contact when I was about to make it return. Surely enough, when the connection finally was reestablished it was already obediently flying home at the selected height, clearing any obstacles by the set appropriate margin.

It is extremely important to not engage flying in a hasty and careless manner but actually to ponder for a while a "geometric picture" of what we are about to be doing.

MK

 

[AAPhoto]

For other new pilots reading this thread, VLOS (visual line of sight) isn't the only rule that was broken here. From the looks of it, flying over a populated area and flying in class B airspace (OK for a part 107 licencee with permission, but not OK for the unlicensed) can be added to the list.

A warning should appear in the DJI GO app regarding the airspace. Can the OP confirm if there was a warning displayed in the app? (Assuming all warning notifications were not disabled)

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[Death from Above]

For other new pilots reading this thread, VLOS (visual line of sight) isn't the only rule that was broken here. From the looks of it, flying over a populated area and flying in class B airspace (OK for a part 107 licencee with permission, but not OK for the unlicensed) can be added to the list.

A warning should appear in the DJI GO app regarding the airspace. Can the OP confirm if there was a warning displayed in the app? (Assuming all warning notifications were not disabled)

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A warning did appear on the app. You can view all the warnings on the healthydrone link provide at the start of the thread.


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[damaltor]

Flying among all these medical center buildings and past the helipad, probably wasn't a wise thing to do.

 

[Cookedinlh]

I'd say the only issue is the lack of experience in operating djiGO. If this was only the second flight by a non-pilot with limited drone hands-on experience I'm not surprised it was lost on such a flight . . 98 feet AGL and a mile away (~5200ft) . Chalk it up to experience and get some closer-in experience with all the modes and features before you try again. dji is right . . it was likely a fully functional Mavic throughout the "flight".